Effects of nutritional factors on reproduction, growth, preweaning reflex development and postweaning learning...

1. Dietary high protein intake in stroke-prone spontaneously hypertensive rats (SHRSP) induces a reduction of blood pressure and decreases the incidence of cerebral lesion. The objective of this investigation was to determine the effects of nutritional factors of dietary high protein on reproduction, growth, preweaning reflex development, postweaning behaviour and learning performance in SHRSP. 2. SHRSP were fed on a high protein rat diet (OA2 diet) and a standard rat diet for SHRSP (FSP diet). Rats were mated by brother-sister combinations and observed on reproductive performance, preweaning reflex development and postweaning learning performance among the 3rd to the 6th generations. 3. OA2 showed some advanced responses at the preweaning period compared to FSP in the surface righting, negative geotaxis and mid-air righting reflexes. 4. At the postweaning period, hyperactivity of OA2 was indicated at the open field test. In the ambulatory activity of the circadian rhythm, OA2 was better synchronized with running activity in the light and dark alternation cycle. 5. OA2 group indicated the higher postweaning learning performance in the water E, the water multiple T (Biel) and the Morris water-maze test as well as the acquisition of the conditioned avoidance response test. 6. In conclusion, dietary high protein intake in SHRSP produced some advanced effects on preweaning reflex development and postweaning learning performance.